Hereditas · 2003 · 17 citations · 19 references
The karyotypes of the bat species Molossus ater, M. molossus (2n = 48; NF = 64) and Molossops planirostris (2n = 34; NF = 60) were analyzed by G-, C-banding, silver nitrate staining (AgNO3), base-specific fluorochromes and fluorescent in situ hybridization (FISH). The two species of Molossus presented the constitutive heterochromatin (CH) in the pericentromeric regions of all autosomes and in the X chromosome, while the Y chromosome was completely heterochromatic. Molossops planirostris showed conspicuous CH blocks in the pericentromeric regions of the pairs 4, 5, 8, 15, 16 and in the short arm of the X chromosome, while the Y did not present any CH block. Pretreated slides for C-banding stained with DAPI (CB-DAPI) revealed a similar pattern of C-banding (CBG) for these species. Sequential staining (AgNO3/CMA3/DAPI) in M. planirostris showed that the nucleolus organizer regions (NORs) are weakly CMA3 positive and DAPI negative. In the three species, triple staining with CMA3/DA/DAPI revealed R-banding with CMA3 and uniform staining with DAPI. The ribosomal cistrons detected by FISH were present only in the pair 5 in both species of Molossus, and in two pairs of medium sized chromosomes (pairs 9 and 10) of Molossops planirostris. The results obtained by FISH, compared with those by AgNO3 staining, indicated that all NORs in these species are transcriptionally active.
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